Sliding miter saws have rendered them obsolete mostly due to safety and portability. Also, a Xcut sled can do most things an RAS does more safely.
The problem is typical saw (CM, Ridgid, etc) is 1) woefully underpowered 2) horrible at keeping settings and 3) cheaply built. I have a Ridgid which I use and I scratch my head everytime I read of someone who loves these saws because all you have to do is tap them and you're recalibrating the saw.
The old iron Dewalt/AMF saws are great if you can find one but the problem with them will be 40-60 year old motors.
Other than that, any modern RAS worth its salt is far too expensive to warrant in a hobby shop.